It is previously known to give commands to a robot by touching it. For example, an operator may start and stop a work cycle of a robot by giving the robot a push. The existing systems for detecting the commands are based on external sensors on the robot. A torque sensor positioned at a joint of the robot may for example detect an external torque exerted on that joint as a result from the operator pushing a robot arm. It may be necessary to compare a measured torque with an expected torque in order to be in the position of detecting an external torque. The expected torque would typically be based on a reference measurement where the work cycle of the robot is executed without external torques being present. When a presence of a certain torque indication at the respective joint is determined in beforehand to be interpreted as a command to the robot controller, the robot controller may execute the command upon detecting that a torque behaviour corresponding to the torque indication is present.
Basing the detection of commands on external torque sensors requires sophisticated sensors to be positioned at the robot joints. Moreover, if the detection of an external torque is based on a reference measurement, no external torque can be detected during arbitrary robot movements that are executed for the first time. Thus, there remains a desire to improve the existing robot controlling systems such that no external torque sensors and/or reference measurements are required.
One object of the invention is to provide an improved method for controlling an industrial robot by touch.